GUIDE TO THE BEST KNIFE STEEL
Written by Blade HQ Staff Writer Andrew Hamilton on 9/25/2018
From designer, country of origin, blade length, and beyond, there’s a bunch of different factors to consider when buying that new knife. But what about blade steel? Is blade steel a mystery to you? Don’t know 20CV from M4? Is Crucible still just a play by Arthur Miller in your mind? Does Bohler-Uddeholm sound like a stinky cheese to you? Don’t worry—we’re going to break down all the best blade steels you can expect to find at Blade HQ and beyond! Give this article a gander, and you’ll be halfway to an Ivy League degree as a metallurgist (no uhh…not really, but we all start somewhere).
TLDR (Too Long Didn’t Read)
Great For EDC (Everyday Carry)
Great For Fixed Blades
Blades are designed to cut—that’s obvious enough. But when it comes to getting the job done there are four main factors that determine steel quality.
EDGE RETENTION/WEAR RESISTANCE
Edge Retention (also called strength) is your knife’s ability to hold sharpness during use. Whether it’s dicing up cardboard boxes, feather sticking some firewood, or hacking up sisal rope, no one likes a dull knife. It’s remarkable the increased performance you find in cut tests when comparing premium steels to the low end.
A tough blade steel resists chips and total failure when subjected to beating, impact, twisting, and torsion. Tough blade steels are ideal for camping and hard-use. Where a normal steel would chip, these knives can sustain intense batoning sessions, power through staples, and glide through steel strapping.
Are you in a humid, wet, salty environment? Do you frequently use your knife to meal prep acidic ingredients like citrus or tomatoes? Certain steels are so good at resisting rust and corrosion that they can be left permanently submerged without ill-effect. Carbon steels will pit and rust aggressively in wet environments if not properly cared for.
EASE OF SHARPENING
Maybe one of the most frequently overlooked aspects of blade steel is sharpenability. Touching up certain steels with your sharpening stone is an easy, pain-free process whereas harder steels can make for an all-day affair to bring them back to sharp. Additionally, being able to field sharpen your knife can be the difference between life and death in the wilderness.
Blade steel is totally a super important factor to consider when buying a knife, but it isn’t the be-all and end-all. Heat treat, blade geometry, the job at hand, and the sharpening of the blade all play a massive role in the performance of the steel.
Heat Treatment is the process of hardening and tempering the blade steel. This increases the strength of the edge tremendously. A well-done and consistent heat treat goes a long way towards the performance of a knife. High hardness (60 HRC+) increases the edge retention of the steel at the cost of brittleness. Low hardness increases toughness at the cost of edge strength.
Blade geometry is a subject that deserves its own article, but here’s a summary in simplest terms. Cutting and slicing performance will increase as the thickness behind the edge decreases. Additional considerations include the thickness of the blade stock and the primary grind. Knives such as the Spyderco Chaparral have a very thin edge at only .014”. In contrast, a thicker blade stock with more material at the edge will yield a tougher knife like the Ka-Bar Becker BK2.
Sharpening goes hand in hand with blade geometry. A 30 degree inclusive edge means that each side of the blade is sharpened to 15 degrees. Inherently, more acute sharpening angles will see better cutting performance than more obtuse angles. In contrast, a more obtuse angle will be more stable and durable.
CUTTING TASK/THE JOB AT HAND
Often overlooked is the job at hand. When you put your knife to work, what tasks will it need to conquer? Knife steels that exhibit extreme hardness and edge retention are amazing at cutting through warehouses full of cardboard but hit a staple and your knife may suffer a chip. Tough steels excel at camp chores and batoning wood but are unable to be used at very thin edge profiles while maintaining edge stability. In reality, there is no perfect blade steel in the same way that there is no perfect knife. Consider your use case to choose the perfect knife for you.
STRENGTH VS. TOUGHNESS
The best blade steels exhibit a balance of strength and toughness. Blade steels with an insane amount of hardness (pushing towards 70 HRC) tend to lack stability and can suffer from cracks, chipping, and total failure. Extremely tough blades may not cut as well as desired and can suffer from edge rolling and difficulty maintaining an edge.
BOHLER UDDEHOLM M390
Bohler M390 exhibits excellent hardness and edge retention, corrosion resistance, and very good toughness. This steel is currently many consumer’s favorite, which has led top companies to widely utilize this steel.
CTS-204P AND CPM-20CV
Bohler M390, CTS-204P, and CPM-20CV are essentially the same steel and sport a near identical composition with significant amounts of Chromium, Molybdenum, Vanadium, and Tungsten. CTS-204P is made by the USA-based Carpenter Technology Corporation while CPM-20CV comes from Crucible Industries.
CPM-S90V AND CPM-S110V
Popular among both Benchmade and Spyderco, CPM-S90V is a steel known for its excellent edge retention and very good corrosion resistance. This blade steel exhibits good toughness, but it does not meet the standards of certain more popular fixed blade steels and even the performance of M390.
CPM-S110V exhibits many of the same qualities as S90V. The primary difference is out-of-this-world edge retention at the cost of some minimal toughness. If you frequently use your knife to slice up cardboard, there may not be a better steel than CPM-S110V. Both of these steels are a real bear to sharpen up!
Bohler-Uddeholm produces more than just the famous M390 steel. Consider Elmax if toughness is high on your list. Excellent strength and toughness are balanced with very good sharpenability and corrosion resistance. Elmax is an amazingly well-rounded steel when you take all of these factors into consideration.
Carpenter produced CTS-XHP is another well-rounded and versatile steel. Equally at home as an EDC folder or as a fixed blade, this blade steel is easy to sharpen, corrosion resistant, and mixes very good edge retention with sufficient toughness. Spyderco and Cold Steel frequently utilizes this steel.
Crucible Industries has a real gem on their hands with CPM-M4… At the cost of some corrosion resistance you get amazing edge holding, toughness, and decent enough sharpenability. Based on experience and testing, M4 steel may outperform blade steels such as M390 and S90V in terms of edge retention and definitely toughness. Some people are uncomfortable carrying a knife that is susceptible to rust and corrosion, but keep your blade oiled and you won’t have any problems.
CPM-S30V AND CPM-S35VN
Chris Reeve is famous for developing two steels with Crucible Industries, and boy did this partnership result in a great product. S30V is in many eyes the ultimate EDC steel. Exhibiting very good edge retention, corrosion resistance, and sharpenability, S30V is utilizied by many manufactures.
CPM-154 and 154CM
It may seem like there’s a big step down between a steel like S110V and CPM 154. Realistically, in normal day to day use you would struggle to pick out any differences. CPM 154 is an excellent EDC blade steel with above average edge retention, corrosion resistance, and ease of sharpening.
Both great steels, CPM 154 benefits from a powdered metallurgy and is finer grained than 154CM. Powdered steels are more consistent, have better edge retention, and improve toughness due to a lack of inclusions.
CPM-3V and CPM-4V
CPM-3V is in many ways the perfect blade steel for a fixed blade knife. Insanely tough, this steel also manages to boast excellent edge retention and corrosion resistance. CPM-4V boosts the edge holding when compared to 3V, but at the cost of some slight toughness.
A2 has long been known as the classic standby for a fixed blade steel. Compared to CPM-3V, A2 is available more much affordably and is much more easily sharpened. Edge retention and toughness are very good.
O1 is a small step below A2 in terms of blade steel performance. With slightly decreased edge holding and a tendency to rust, O1 performs very well despite requiring maintenance.
D2 has been a popular steel dating back to WWII. Prone to rusting and corrosion, but not a problem if blade is kept oiled. Good edge retention, toughness, and sharpenability. D2 is one of those most ubiquitous steels.
VG-10 exhibits many of the same qualities of 154CM with the largest difference being an increase in corrosion resistance. Fully good-to-go, VG-10 may be one of the most neutral balanced steels on the market.
There’s no doubt-H1 is a specialty steel. When we call a normal steel stainless, it really means just that-the steel will stain LESS than carbon steel. The difference with H1 is that you can literally leave it in salt water forever and it won’t rust. If you’re interested in the perfect fishing knife, look no further. Such amazing corrosion resistance comes at a cost, as this steel does not exhibit excellent wear resistance, edge holding, or toughness.
LC200N is an amazing steel! With 90% the corrosion resistance of H1, you also get much improved edge retention. Where H1 steel lives in a specialist category as a fishing or boating knife, LC200N holds its own as an EDC blade steel. If you live in a humid environment or frequently meal prep with your pocket knife, try the Caribbean from Spyderco in LC200N steel.
N690 is an extremely ubiquitous and popular steel among knifemakers in Europe. Strength and toughness are comparable to that found on VG-10 or 154CM. This steel has extremely good corrosion resistant properties.
CPM stands for Crucible Particle Metallurgy. Essentially, CPM steel is produced from a very fine power of carbide particles. This allows for a very uniform distribution of carbides throughout the steel structure during solidification. Compared to cast steels, ingot based CPM steels have a very fine grain structure and have far fewer inclusions. Finer grained powdersteels can take a sharper edge.
Damascus or ‘pattern welded’ steel is a result of combining two steels together. As such, the performance of the steel is entirely dependent upon the steels being utilized. The vivid patterns visible in Damascus steel come from the acid etching process in a ferric chloride solution. Steels patina in the acid at varying rates which allows for one steel to etch darker than the other and show that famous patterned contrast.